Came across these links on the Extension.org site. Thought there might be some interesting information for you MG’s here.
Hypertufa is a man-made version of a natural rock known as tufa, a very porous rock that was once used for stone watering troughs. It can be used for anything from a simple pot to elaborate garden art.
The items you will need include the following:
- Large bin or wheelbarrow to mix the ingredients in
- Hoe or trowel to mix and scoop with
- Some type of mold; box, plastic bowl, bucket, bin or a wet sand mold
- A release agent, either cooking spray or a plastic bag
- Ingredients: Portland cement, peat moss, perlite, vermiculite, sand
- Fortifier (optional)
- Colorant (optional)
You will also need
- Heavy-duty water proof gloves
- Eye protection
- Dust mask
- Old clothes and shoes that you don’t mind ruining
You should have everything ready before you start. If you are using the outside of a box, cover it with the plastic bag and be sure it is on a level surface, preferrably one that won’t need to be moved for a day. If you are using a bowl or bucket or other type of mold, be sure to coat it with the cooking spray.
There are many variations of the basic hypertufa recipe, but the three basic ingredients are Portland cement, some type of aggregate to keep the object from becoming too heavy, and water.
Portland cement is not the same thing as concrete, although it is one of the ingredients in concrete. You can use basic gray or white Portland cement if you would like to add color to your mix. You can pick up concrete color at the local home improvement store.
The aggregate can be peat moss, perlite, vermiculite or sand. I usually use two aggregates (peat moss and vermiculite) and Portland cement in three equal parts. This will make the mix light and porous.
You may want to add a fortifier. There are commercially made bonding agents, but they can get a bit pricey. Some people use Elmers white or wood glue. Whatever you use it must be water soluable. Do not use Gorilla Glue or similar products. If you add a fortifier and color you want to mix these with the water first.
Add all the dry ingredients in the wheelbarrow and mix thouroughly before adding water. Add water until you can roll the mixture into a ball and it holds it’s form. You don’t want too much water or it will affect the curing and compromise the object’s strength. Fill your mold or apply mixture to outside of box until about two inches thick. Smooth the mixture until it is an even depth across the mold. Once the piece has set, for about 24 hours, remove it from the mold and set it in a damp, cool place to cure for several weeks. The longer the cure time the stronger your piece will be.
Before planting in your new bowl, soak in clear water for a day, rinse, soak again for a day, then drain and let it dry. This removes any extra alkalinity from the piece. If you want moss to grow on your piece, either wait for nature to take it’s course or brush on a little buttermilk. You can grind up some moss and mix it with the buttermilk to speed the process further.
Now that you’ve mastered the basics there’s no limit to what you can make, only your imagination.
If you are interested in attending a hypertufa workshop contact the NSVMGA County Coordinator in your county.